package com.example.xiaozhi.democ;

import android.database.Cursor;
import android.net.Uri;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {

    private Button btnQuery;
    private TextView txtResult;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

       txtResult=findViewById(R.id.txt_result);
        btnQuery=findViewById(R.id.btn_query);
        btnQuery.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Uri uri=Uri.parse("content://com.gdcp.student/student");
                Cursor cursor=getContentResolver().query(uri,null,null,null,null);
                if (cursor!=null&&cursor.getCount()>0){
                    StringBuffer buffer=new StringBuffer();
                    for (cursor.moveToFirst();!cursor.isAfterLast();cursor.moveToNext()){
                        String stuno=cursor.getString(0);
                        String name=cursor.getString(1);
                        int age=cursor.getInt(2);
                        buffer.append(stuno).append(" ").append(name).append(" ").append(age).append("");
                    }
                    txtResult.setText(buffer);
                }else{
                    txtResult.setText("已清空");
                }
            }


        });
    }
}
